/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.confignode.manager.node.heartbeat;

import org.apache.iotdb.commons.cluster.NodeStatus;
import org.apache.iotdb.mpp.rpc.thrift.THeartbeatResp;
import org.apache.iotdb.tsfile.utils.ReadWriteIOUtils;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.util.Objects;

public class NodeStatistics {

    // For guiding queries, the higher the score the higher the load
    private long loadScore;

    // The current status of the Node
    private NodeStatus status;
    // The reason why lead to the current NodeStatus (for showing cluster)
    // Notice: Default is null
    private String statusReason;

    public NodeStatistics() {
        // Empty constructor
    }

    public NodeStatistics(long loadScore, NodeStatus status, String statusReason) {
        this.loadScore = loadScore;
        this.status = status;
        this.statusReason = statusReason;
    }

    public long getLoadScore() {
        return loadScore;
    }

    public NodeStatus getStatus() {
        return status;
    }

    public String getStatusReason() {
        return statusReason;
    }

    public void serialize(OutputStream stream) throws IOException {
        ReadWriteIOUtils.write(loadScore, stream);
        ReadWriteIOUtils.write(status.getStatus(), stream);
        if (statusReason != null) {
            ReadWriteIOUtils.write(true, stream);
            ReadWriteIOUtils.write(statusReason, stream);
        } else {
            ReadWriteIOUtils.write(false, stream);
        }
    }

    // Deserializer for consensus-write
    public void deserialize(ByteBuffer buffer) {
        loadScore = buffer.getLong();
        status = NodeStatus.parse(ReadWriteIOUtils.readString(buffer));
        if (ReadWriteIOUtils.readBool(buffer)) {
            statusReason = ReadWriteIOUtils.readString(buffer);
        } else {
            statusReason = null;
        }
    }

    // Deserializer for snapshot
    public void deserialize(InputStream inputStream) throws IOException {
        loadScore = ReadWriteIOUtils.readLong(inputStream);
        status = NodeStatus.parse(ReadWriteIOUtils.readString(inputStream));
        if (ReadWriteIOUtils.readBool(inputStream)) {
            statusReason = ReadWriteIOUtils.readString(inputStream);
        } else {
            statusReason = null;
        }
    }

    public static NodeStatistics generateDefaultNodeStatistics() {
        return new NodeStatistics(Long.MAX_VALUE, NodeStatus.Unknown, null);
    }

    public NodeStatistics deepCopy() {
        return new NodeStatistics(loadScore, status, statusReason);
    }

    public NodeHeartbeatSample convertToNodeHeartbeatSample() {
        long currentTime = System.currentTimeMillis();
        return new NodeHeartbeatSample(
                new THeartbeatResp(currentTime, status.getStatus()).setStatusReason(statusReason),
                currentTime);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        NodeStatistics that = (NodeStatistics) o;
        return loadScore == that.loadScore
                && status == that.status
                && Objects.equals(statusReason, that.statusReason);
    }

    @Override
    public int hashCode() {
        return Objects.hash(loadScore, status, statusReason);
    }

    @Override
    public String toString() {
        return "NodeStatistics{"
                + "loadScore="
                + loadScore
                + ", status="
                + status
                + ", statusReason='"
                + (statusReason == null ? "null" : statusReason)
                + '\''
                + '}';
    }
}
